/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.db.wal.io;

import org.apache.iotdb.db.wal.buffer.WALEntry;
import org.apache.iotdb.db.wal.buffer.WALEntryType;
import org.apache.iotdb.db.wal.buffer.WALSignalEntry;
import org.apache.iotdb.db.wal.utils.WALFileStatus;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.ByteBuffer;

/**
 * WALWriter writes the binary {@link WALEntry} into .wal file.
 */
public class WALWriter extends LogWriter {
    public static final String MAGIC_STRING = "WAL";
    public static final int MAGIC_STRING_BYTES = MAGIC_STRING.getBytes().length;

    private WALFileStatus walFileStatus = WALFileStatus.CONTAINS_NONE_SEARCH_INDEX;

    /**
     * wal files' metadata
     */
    protected final WALMetaData metaData = new WALMetaData();

    public WALWriter(File logFile) throws FileNotFoundException {
        super(logFile);
    }

    /**
     * Writes buffer and update its' metadata
     */
    public void write(ByteBuffer buffer, WALMetaData metaData) throws IOException {
        // update metadata
        updateMetaData(metaData);
        // flush buffer
        write(buffer);
    }

    public void updateMetaData(WALMetaData metaData) {
        this.metaData.addAll(metaData);
    }

    private void endFile() throws IOException {
        WALSignalEntry endMarker = new WALSignalEntry(WALEntryType.WAL_FILE_INFO_END_MARKER);
        int metaDataSize = metaData.serializedSize();
        ByteBuffer buffer =
                ByteBuffer.allocate(
                        endMarker.serializedSize() + metaDataSize + Integer.BYTES + MAGIC_STRING_BYTES);
        // mark info part ends
        endMarker.serialize(buffer);
        // flush meta data
        metaData.serialize(buffer);
        buffer.putInt(metaDataSize);
        // add magic string
        buffer.put(MAGIC_STRING.getBytes());
        write(buffer);
    }

    @Override
    public void close() throws IOException {
        endFile();
        super.close();
    }

    public void updateFileStatus(WALFileStatus walFileStatus) {
        if (walFileStatus == WALFileStatus.CONTAINS_SEARCH_INDEX) {
            this.walFileStatus = WALFileStatus.CONTAINS_SEARCH_INDEX;
        }
    }

    public WALFileStatus getWalFileStatus() {
        return walFileStatus;
    }
}
